Two clay balls collide and stick. Ball 1 has a mass of 10 kg and an initial velocity of 5 m/s in the positive x direction. Ball 2 has a mass of 20 kg and an initial velocity of 5 m/s in the negative x direction. What is the final velocity of the combined mass?

- 1.67 m/s

Explanation:

mass of first ball, m = 10 kg

mass of second ball, M = 20 kg

initial velocity of first ball, u = 5 m/s

initial velocity of second ball, U = - 5 m/s (direction is opposite to the first ball)

Let the final velocity of the combined mass is V.

Use the principle of conservation of linear momentum

Momentum before collision = Momentum after collision

m u + M U = (m + M) V

10 x 5 + 20 x (-5) = (10 + 20) x V

50 - 100 = 30 V

- 50 = 30 V

V = - 1.67 m/s

Thus, the combined mass moves in the negative x axis direction with the velocity of 1.67 m/s.